This research will develop a model for the production of neurobehavioral toxicity from aluminum administered by the peripheral route. Adult rabbits will be daily injected, via the subcutaneous route, for 20 days with one of several doses of aluminum ion. After the end of the aluminum exposure, at which time neurobehavioral toxicity should have developed, several measures will be exployed to quantitate the level of toxcity produced: rate of acquisition and retention of responding of the nictitating membrane of the rabbit in a classical conditioning experimental paradigm, magnitude and retention of an acquired aversion to saccharin solution which has been paired with aversive rotation in the conditioned taste aversion paradigm, extent and degree of neuro-fibrillary degeneration produced in selected brain region and level of aluminum and phosphorus in those same brain regions as well as selected peripheral tissues. Results from these bahavioral, histological and analytical analyses will be compared to determine if they positively covary. These results will be compared to the level of aluminum exposure to determine if there is a positive correlation between degree of toxicity and total toxic exposure. Positive results from this study will provide a model for future investigations into the factors influencing the development of aluminum induced neurobehavioral toxicity, specifically: route of exposure, age of the organism when exposed, status of renal function of the exposed organism, level of endogenous hormones such as parathyroid hormone and others.